Question

complete the series 24,21,18,15​

Answer 1

Answer:

=>n=26. So,26 terms of AP series 24+18+15+... Will have to be taken continuously so that their sum is -351. Hope it helps...

Step-by-step explanation:

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Answer 2

In the given arithmetic series, a=24,d=−3

Let us find n such that S

n

=−351

Now, S

n

=

2

n

[2a+(n−1)d]=−351

That is,

2

n

[2(24)+(n−1)(−3)]=−351

⇒

2

n

[48−3n+3]=−351

⇒n(51−3n)=−702

⇒n

2

−17n−234=0

⇒(n−26)(n+9)=0

⇒n=26 or n=−9

Here n, being the number of terms needed, cannot be negative.

Thus, 26 terms are needed to get the sum −351.